Dynamo-electric machine.



UNrrnDl Lerares i)airain onirica SVEN'R. BERGMAN,OF LYNN; MASSACHUSETTS,ASSIGNOR TO GENERAL ELECTRIC COMPANY, i A CORPORATION OF NEW YORK.

vwithout 'their attendant disadvantages.

. producing Bynum-ELECTRIC MACHINE.

Specification of Letters Patent. v

Patentes Jes. ai, ieee.

To all lwhom tf/nay concern:

it known that I, SVEN R. Ennemis, ya subject of the King otweden,residing at Lynn, county of Essex, State of Massachusetts, have'invented certain new and usefui Improvements in 'Dynamo-ElectricMachilies, of which the following is a specification. l

My inventionrelates to dynamo-electric machines, and particularly to therotorsbof vide a'novelconstructionfor obtaining the dvantages. of bothclosed and open slots Electrically, closed slots present certainadvantages compared to open slots, since, by reducing the reluctance ofthe airap, the niagnetiziiig current is reduced, and, .bygixeateruniformity in the airsgap, eddyvcurrent losses in the statorteeth are reduced, Thus, bothl the power-factor and the eli'iciency ofthe rnotoli` are. improved, Mechanically, however, the closed slotconstruction possesses disadvantages, first, because the. diesrequiredfor punching the laminations are more eX ensive and more easily broken,and secon because, if a coil yvinding is employed,` the cost of theWinding is greatly increased, since former-Wound,

coils cannot be used.

My inventionconsists in arranging the core With open slots a Wrapping ofmagnetic material arranged to enter and magnetically to close theslots..

This Wrapping may be conveniently formed by a sheet-metal punchingpreferably of a tilie sheet may be secured after it is applied to thecore. 'lhe ends of the together by riveting,

'c0re, or the ends may be Welded together,

so as to form a continuous cylinder before it is ap lied to the core. Inthe .latter case the cy inder is made originally with a slightly largerdiameter than the core, and, after it is s ip ed into position, isdented or drawn inwar at one or more points, so as to reduce itsdiameter to that of the core and to pull `it into the slots oi the core.to permit this drawing in of the cylinder, one or more oi` the slots inthe cylinder are made extra wide, as Will be hereinafter explained, l.

Myinvention Will be best understood by and applying to the coreln orderinduction motors, and its object is to prol lwrapping' on account oi itshigh `in `Figs. 1 and vare made extra wide, as

u s ture-spider carrying the vlarninations B,

core. These laminawhich forni the rotor tions are stamped with openslots", as shown 1n Figi, in which the conductors C are placed. l haveshown these conductors provided with end-rings D forming withaccompaiiyi'ngV drawings, in

the conductors a squirrel-cage Winding, but

itWill be understood that iny invention is 'equallyA applicable toarmaturesl with coil windings. E represents a cylindrical Wrapping whichmay be stamped out yof sheet metal and which forms in effect a secondsquirrel-'cage of magnetic material holding the conductors of the mainWinding in place. Transformer iron is preferably used for thispermeability and high resistance. The ends of the sheet may be rivetedtogether by means oi" a connectiiig-plate F, as is clearly shown 4. Withthis method 'of joining the ends ,oi the cylinder, the cylinder israised above the tops of the conductors C, and the spaces between thecylinderand the conductors are filled by strips or Wedges G, which maybe oi any suitable materialjsuch as wood. Y

A modified method of arranging the sheetsteel Wrapping is-shoWn in Figs.5, 6 and 7.

In this modification the original length of the sheet is made slightlygreater than the pe# riphery'oi the rotor core, and the ends are Weldedtogether before the cylinder is applied to the core. One or more of theslots in the sheet, which pass over the teeth or" the core, shown inFig. 5, so that after the cylinder has been slipped over the core, itmay be dented or' drawn in` at these slots, as shown in .Figs 6 and 7,so as to reduce the diameter of tne cylinder 'to that of the core, andcause the portions of the Cylinder between the slots to enter the slotsin t ie core, wliichoperation reduces the eilectivc bv Letters Patent ofggg 4 it will be seen'thatthe construction del.:

scribed affords the mechanical .advantages of the openslot, and also theelectrical advantages of the closed slot. 't

What i claim as 'new andv desire to secure v the United States, isf- 1.irre dynaino-electricniachne, a laminated core provided with open slots,a Winding carried in said slots, and a continuous Wrapping of magneticmaterial Woundv around said core and entering and closing said siots. yA

2. in a dynamo-electric machine, a laminated core provided Withlopenslots, a Winding carried in said slots, and a cylindrical smaad sheet'oi' magnetic material surrounding Said core and having slots adapted topass over.

the ends of" the'teeth onsaid core.

A3. in a dynamo-electric machine, nated core provided with open ingcarried in said slots, a cylinder formed Vof sheet-metal of highpermeability eurrounding said core and having slots adapted to-pass overthe ends of the teeth on said core. i

4. A rotor for an induction motor comprising' a laminated core providedwith open slots, a winding carried in said slots, and a s uirrel-cageformed of a slotted cylinder oi sheet-metal of high permeability carriedin the top of, and closing, said slots.

v In Witness whereof, I'have hereunto set my hand this sixth day ofMay1907.

SVEN R. BERGMAN lNitn'esses:

`JOHN A. MCMANUS, Jr., PHILIP F. HARRINGTON.

a laini' slots, a'wind-

